Nearly 400 prisoners including militants escaped early Sunday from a jail in northwestern Pakistan after an attack by insurgents armed with guns, grenades and rockets, officials said.

More than 150 heavily-armed Islamist militants stormed the central prison outside the restive northwestern town of Bannu bordering the lawless tribal regions where Taliban and Al-Qaeda linked militants are known to operate.

Ehsanullah Ehsan, spokesman for the Tehreek-e-Taliban Pakistan (TTP) militant group claimed responsibility for the attack.

"In a couple of days when all of them have reached their designated places we will issue details about them. At the moment I cannot give you exact numbers."

The attack started at around 1:00 am (2000 GMT Saturday) and continued for two hours, with militants in cars and pick-up trucks shooting and lobbing grenades to force their way into the prison, a security official told AFP.

"Some 384 prisoners, including some hardcore militants, have escaped during the attack," the official said, asking not to be named.

"Preliminary information suggests that there were some 944 prisoners in the jail according to the tally late Saturday."

"We will investigate why militants were able to carry out such an attack successfully and what the security was doing," he said.

Hussain said the militants blocked all roads leading to the prison to delay the arrival of any reinforcements and targeted six barracks where "dangerous insurgents" were being kept.

Security forces cordoned off the area and arrested some of the escapees, while others returned voluntarily saying they had fled to avoid the gunfire, Hussain said.

A large number of militants had recently been moved to the jail from neighbouring Kohat and Lakki Marwat prisons, which are being converted into centres to rehabilitate former insurgents, the security official said.

A former member of the airforce sentenced to death for an attack on former president Pervez Musharraf was among the escaped militants, he said.

Adnan Rasheed was convicted after a bomb planted under a bridge in Rawalpindi near Islamabad in December 2003 exploded moments after the passing of Musharraf's motorcade. His appeal is pending before the Supreme Court.

Authorities have shut down the mobile phone network in the area and army troops along with paramilitary forces and police have launched a search operation in the area, he said.

Police confirmed the attack and said that 384 prisoners had escaped after the militant raid and 40 of them, including a female prisoners had returned and arrested.

Senior Bannu police official Iftikhar Khan told AFP that at least three police officials were wounded in the attack.

The attackers outnumbered the security forces at the prison and militants fled before reinforcements reached the jail, he said.

Provincial home secretary for Khyber Pakhtunkhwa Azam Khan said 11 prisoners were arrested while 29, inclusing a woman, returned to jail themselves.

"We have expanded the serach operation in the neighbouring towns of Kohat and Lakki Marwat," Khan told AFP.

Live television footage showed prisons huge black steel gate ripped open by explosion and broken doors of prisoner cells, ransacked jail offices and empty bullet shells scattered on the ground.

Pakistan's tribal districts near the Afghan border are rife with homegrown insurgents, Al-Qaeda operatives and Taliban, who are understood to use rear bases in Pakistan to plot attacks in neighbouring Afghanistan.

The mountainous region lies outside direct government control and US drone strikes on militant commanders in the region are a key plank in the US strategy to defeat Al-Qaeda and reverse the insurgency in Afghanistan.

Islamist militants have killed more than 4,900 people across Pakistan since government troops raided an extremist mosque in Islamabad in July 2007.

--

Get stories like this on the Yahoo app and discover more every day.Download it now.